SYNTHETIC VISION SYSTEMS

Of all the safety systems to come along in aviation’s 102-year history- few work by giving more ability to an inherent human capability. Usually they provide an alternative to our senses of abilities. For example- airframe parachutes- poised to expand into VLJs from the handful of piston designs now certified for them- provide an alternative landing capability for the pilot of a stricken aircraft. Safety belts- ...

Dave Higdon writes about aviation from his base in Wichita Kansas. During three decades in...Read More

Seeing Is Believing: Synthetic vision takes spreads through business aviation

Of all the safety systems to come along in aviation’s 102-year history- few work by giving more ability to an inherent human capability. Usually they provide an alternative to our senses of abilities. For example- airframe parachutes- poised to expand into VLJs from the handful of piston designs now certified for them- provide an alternative landing capability for the pilot of a stricken aircraft.

Safety belts- standard aircraft fare for decades longer than cars have used them- work by retraining occupants from rattling around inside a cabin; the latest in human-restraint systems- airbags- are coming to airplanes now and work by providing an air cushion between moving humans and the stationary airframes around them. Such systems add a margin of survival odds when things don’t work as desired.

But one of the newest and fastest growing actually enhances a human sense – the ability to see- arguably the one of our five senses used and treasured most by humans. And the effectiveness of Synthetic Vision Systems comes from their ability to keep things from going wrong to begin with by giving crew enhanced eyesight in low-visibility conditions.

With the ability to see through fog- smoke- snow- even in the dark- pilots can more safely bridge that most-critical phase of any flight: from approach to landing. When the runway environment evades detection until the last couple of hundred feet- the potential increases for something to go wrong – particularly during non-precision approaches.

When- however- the pilot can see the entire airport environment despite clouds- rain- mist- fog or snow- the landing phase feels more like a VFR flight – and safety gains. Such are the simple benefits of some rather complex systems designed to give flight crew 'eyes' that can see in the dark- through the fog- with acuity enough to recognize runway paint- marker lights- buildings- towers- vehicles and people.

Such is the immense benefit package of the modern Synthetic Vision System. As immense as these benefits are though- their costs continue to decline as their applications continue to grow.

Two Favors- Two Different TechnologiesWe call these systems 'Synthetic Vision' systems as if they are all the same- but actually 'Enhanced Vision Systems' best describes the technology dominant in today’s approved gear.

EVS in general employs some form of infrared sensor – some call them 'cameras' – to detect the temperature differences between pavement and dirt- pavement and paint- people- buildings- vehicles- etc. Those sensors generate a signal which- in simple terms- a processor translates into a monochrome image displayed on a screen display. The hotter an object- the brighter its appearance on a screen.

In this case- the system 'enhances' the crew’s vision and displays what it senses for them to see. And SVS works independently of other equipment or data inputs.

The newer approach more closely resembles a true Synthetic Vision System- in that it uses a completely different technological basis to create an image without actually ‘seeing’ anything. Honeywell researchers have demonstrated a synthetic vision system that uses refined terrain and obstacle data from the company’s own enhanced ground proximity warning system (EGPWS) to paint a computer-generated picture of the world ahead on aircraft flight displays.

The concept combines symbols used in Honeywell’s head-up display (HUD) designs and overlays them on a compelling 3D view of hills- mountains- obstacles and runways.

Instead of a monochrome image differentiated by differences in bright and dull objects- Honeywell’s synthesized images display in colors similar to those employed on VFR sectionals.

Regardless of the technological foundation- the goal of both types is to eliminate accidents that grow out of the crew’s inability to see. Given the ability to ‘see’ the runway environment on landing- as well as adjacent terrain when maneuvering in areas with mountains- towers or other obstacles- pilots can avoid the threats.

Two good pieces of news are here to consider. First- the number and costs of these systems are going in opposite directions – availability is up- prices down – with many of them available for retrofit to existing corporate aircraft.

Second and perhaps best of all- the FAA- after some initial- understandable hesitation- recognizes the benefits of EVS by granting aircraft so equipped with the legal latitude to make approaches to airports reporting ceilings as low as 100 feet. These are approaches without auto land equipment to airports that support Category I approaches that pilots can hand fly – because they can see like they have x-ray eyes.

EVS: Seeing Through The MurkIt’s been nearly five years since Gulfstream pioneered EVS with the first FAA approval for a Kollsman system on the GIVSP. The system’s popularity spread so fast and so strongly that the system became standard on Gulfstream’s larger jets – including the G550- G500 and G450 – and an available option on all its other models.

The Gulfstream/Kollsman system is relatively simple: a special cryogenically cooled sensor mounted in a streamlined fairing detects infrared emissions from objects – even through clouds- fog and precipitation - something not all IR sensors can do.

The infrared image collected by the camera is processed and transmitted to a Honeywell Heads-Up Display- which projects the image as if it was ahead of the pilot outside the windshield.

Best of all- Gulfstream can retrofit its system in its jets that weren’t equipped when manufactured.

Bombardier has also adapted a system for its own jets- offering its Bombardier Enhanced Vision System (BEVS) on several models – with retrofit possible on many of the company’s aircraft. This package employs sensors from CMC Electronics in Canada and displays from Europe’s Thales.

Max-Viz- a U.S. firm- has pioneered its own IR EVS system for the Corporate- commercial and military fixed wing and rotor wing markets. According to the company- the Max-Viz EVS 1000 system offers price and performance advantages not previously seen. Today- Max-Viz EVS is certified on over 45 airframes and the firm reports over 200 systems in operation.

In another piece of good news for corporate aircraft operators- Kollsman last fall announced plans for systems below $100-000 – with a long-range goal of halving that price in a few more years. Kollsman’s newest gear takes advantage of new technological advances that reduce the package size and weight (under 10 pounds- total) as much as price – bringing the potential for packages light enough for VLJs- single-engine and twin-engine propjets- and light piston aircraft.

A Pennsylvania-based company- Forward. Vision.™- offers an EVS package developed by a Veterinarian and his partner for his experimental and certified aircraft. Thanks to its diminutive size- large capability and huge price difference- the package is gaining interest from a variety of corporate and military prospects as well as the general aviation community.

Forward. Vision. uses a long-wave sensor that can detect thermal differences through smoke- fog- snow- day or night. The sensor’s output can be displayed on a wide variety of multifunction displays or on any LCD monitor. And the basic package – under four pounds- and under 17 inches long – costs less than $25-000 installed.

The package can be temporarily installed using PIC (Pilot in Command) approval or installed under a Form 337 Field Approval for this price and provide the benefits inherent to SVS- even without the legal approval for use down to 100 feet on IFR approaches. As the company notes- the ability to see in the dark- through fog- smoke or snow- brings its own safety benefits – regardless of the approach approval.

SVS: Complimentary But DifferentThe Honeywell SVS system we addressed above is but one under development that uses GPS and landscape database info to generate a terrain image and proximity warnings. Rockwell Collins is also working on such a system and has been testing its gear on a Gulfstream under contract to NASA.

As a refresher- these systems use the terrain data of an EGPWS system and GPS input to generate a color picture of the terrain below similar to that on a VFR chart. At least- that’s the view when the computer processor in this system deems separation at a level that poses no risk to the flight.

Come too close to terrain- get too low or in proximity to a charted obstacle- however- and the processors turn the area of concern an alarm red as the EGPWS sounds off with its aural warning.

This system may someday be able to include input from ground sensors – such as airport movement systems – to also show the location of vehicles and other airplanes- bringing its capability closer to real vision.

Test pilots from NASA and Gulfstream began flying a GV equipped with a synthetic-vision system in 2004- with the goal of exploring advanced-vision and runway-incursion technologies that engineers say can one day be brought to civil aviation.

Flying with the computer-generated images of the terrain- the NASA tests involved pilots flying a variety of instrument approaches to the agency’s Wallops Flight Facility in Virginia using only the SVS image for visual guidance.

NASA also tested a system that combined runway-incursion prevention system with SVS- both under the umbrella of NASA’s Aviation Safety and Security Program. This program researches and evaluates new onboard systems that are intended to improve pilot situational awareness and reduce controlled-flight-into-terrain accidents and runway incursions.

Hybrid Systems Coming Other names involved in developing some form of SVS- EVS or a blend include BAE Systems and Nav3D. Both companies have signaled work in sensor and software technology for emerging cockpit advanced-vision systems.

BAE Systems combines forward-looking sensors with detailed terrain and airport databases – similar to other companies’ offerings- but with an interesting difference. Instead of relying exclusively on infrared (IR) cameras for views ahead of the aircraft- BAE Systems plans to combine short- and long-wave IR sensors with a synthetic view generated by a millimeter-wave radar in a process that merges all three images into a single homogeneous picture displayed on a HUD.

Another system has been evaluated by dozens of pilots flying NASA’s Boeing 757 out of the Langley Research Center in Hampton- Virginia. This system is the brainchild of engineers at Nav3D- of San Carlos- California.

The Goal Remains The Same Regardless of whether you’re talking about existing EVS gear- upcoming SVS hardware- or future hybrids- the goal remains the same: to reduce or eliminate accidents under several headings – controlled flight into terrain- mid-air collisions- instrument-approach accidents due to spatial disorientation- even ground collisions in low-visibility conditions.

This new vision-enhancing technology also offers enhanced efficiency by allowing pilots to fly approaches to lower decision heights- improving the crew’s prospects for seeing the runway and completing the flight- if not exactly on-time- at least at the desired destination.

After years as the exclusive purview of military institutions- EVS has already established itself as must-have gear in high-end business jets like the G550 and Global 5000. Now it’s trickling down to smaller jets- turboprops and pistons.

Expect nothing less than more capabilities- greater selection- a broader array of approved aircraft- and lower prices- as SVS and EVS continue to advance and mature. That means it’s only a matter of time before you can afford to let your crew see the light – regardless of your aircraft type or budget.